Theoretical Basis Carbohydrate

THEORETICAL BASIS CARBOHYDRATE The name carbohydrate comes from the French hydrate de carbon given based on the empirical formula (Cm(H2O)n. This formula is obtained from the results of analysis of several sugars show that it is a carbon compound contains hydrogen and oxygen in a ratio of 2 to 1. Although the name is imprecise because carbohydrate means carbon that binds water, however in the literature it is still used. Further research resulted in the following formulation: 1. Carbohydrates are all kinds of sugar that come from nature, such as starch, cotton and cellulose. 2. Carbohydrates are a class of substances in the form of polyhydroxy aldehydes or polyhydroxy ketones, or compounds that can be hydrolyzed into substances the. Carbohydrates are built from one monomer so they can be divided into four groups namely: a. Monosaccharides, namely carbohydrates that cannot be hydrolyzed into even simpler compounds, for example glucose, fructose, galactose and others. b. Disaccharides, namely carbohydrates that can be hydrolyzed into two monosaccharides, for example sucrose, lactose, maltose and others. c. Oligosaccharides, namely carbohydrates that can be hydrolyzed into several types monosaccharides. d. Polysaccharides, namely carbohydrates that can be hydrolyzed into many forms monosaccharides, for example starch, cellulose, glycogen, dextrin and araban. Substances that are monosaccharides can be referred to by their general names based on the number of C atoms based on the type of carbonyl group or based on both, for example: 1. Monosaccharides that contain an aldehyde group are called aldoses, whereas Monosaccharides containing ketone groups are called ketoses. 2. Monosaccharides with 3 carbon atoms (C=3) are called trioses, monosaccharides with the number of atoms C=4 are called tetroses, monosaccharides with the number of atoms C=5 is called pentose, and monosaccharides with the number of atoms C=6 is called hexose. 3. Monosaccharides with the number of C=6 atoms containing an aldehyde group called aldohexose, and monosaccharides with the number C=6 which containing a ketone group is called ketohexose. Disaccharides are further divided into reducing sugars and non-reducing sugars. Sugar reducing agents will show a positive reaction to Tollen's, Fehling's and solutions Benedict. An example of reducing sugar is lactose, while non-reducing sugar an example is sucrose. HOW IT WORKS BENEDICT TEST Carbohydrates that have free aldehyde or ketone groups are easy to use reduces alkaline copper solutions to form cuproxide (Cu2O) precipitates brick red. Ways of working 1. Provide 3 test tubes and fill them with: 2. Heat all tubes in a boiling water bath for 5 minutes and observe. 3. A green, yellow, or brick red precipitate proves its presence free monosaccharides or aldehydes (ketones). SELLIWANOFF TEST Selliwanoff's reagent contains 0.05% resorcinol in 3 N HCl. Reaction Selliwanoff based on the later formation of 4-hydroxy-methyl-furfural condenses with resorcinol to form a red or red colored complex young. This test is specific for carbohydrates that contain ketone groups (ketose). Other carbohydrates in high concentrations can provide similar results. How it works 1. Provide 4 test tubes and fill them 2. Boil each tube for approximately 3 minutes in a water bath. 3. Observe the color change. Red or pink color indicates presence ketose (ketone group). TEST FOR THE CONVERSION OF ALDOSE INTO KETOSE AND VIVAS If glucose is in a dilute base such as Ba(OH)2 or Ca(OH)2, the group Its function changes from aldehyde to ketone to form fructose. The opposite change occurs if fructose is dissolved in a dilute base so glucose is formed. Ways of working: 1. Provide 6 test tubes and fill them: - Tube a: 0.5 ml saturated Ba(OH)2 + 0.5 ml 0.01 M fructose - Tube b: 0.5 ml saturated Ba(OH)2 + 0.5 ml 0.01 M glucose - Tube c: 0.5 ml saturated Ba(OH)2 + 0.5 ml 0.01 M lactose - Tube d: 0.5 ml water + 0.5 ml fructose 0.01 M - Tube e: 0.5 ml water + 0.5 ml glucose 0.01 M - Tube f: 0.5 ml water + 0.5 ml lactose 0.01 M 2. Shake each tube and add 1 drop of Toluene to it. 3. Cover the mouth of the tube with cotton and leave it until the next day. 4. Perform the Selliwanoff test on each tube. 5. Which tube shows the greatest ketose concentration? IOD TEST Iodine forms colored adsorption complexes with polysaccharides. Starch produces a blue color with iodine, while glycogen and starch are hydrolyzed some produce a red-brown color with iodine. Ways of working: 1. Add a little starch, dextrin, gum arabic, gelatin and glycogen to the mixture in different grooves of the porcelain test board. 2. Add 2 drops of dilute iodine solution into the indentation. 3. Look at the color changes that occur.